docs: def mol3d(self):
          """ Return record in MOL format with 3D coordinates calculated """
          if self._mol3d is None:
              apiurl = 'http://www.chemspider.com/MassSpecAPI.asmx/GetRecordMol?csid=%s&calc3d=true&token=%s' % (self.csid,TOKEN)
              response = urlopen(apiurl)
              tree = ET.parse(response)
              self._mol3d = tree.getroot().text
          return self._mol3d